Globally, effects of climate change have caused crisis of environmental destruction and high oil price, and with the accelerated depletion of oil energy and environmental pollution, the development of new and renewable energy and related devices has become urgent.
In this situation, technical development focuses on new and renewable energy development using natural energy such as wind power, tidal power, solar power, and hydro power, and solar cells are a typical example.
Types of solar cells include mono-crystalline and poly-crystalline silicon solar cells, a compound-based thin film solar cell such as CIGS (copper indium gallium selenide thin-film solar cells), DdTe (cadmium telluride thin-film solar cells), and other organic-substances, dye-sensitized and nano-particle solar cells, but all such solar cells and solar cell modules have a problem that efficiency of the solar cells and solar cell modules is significantly reduced under increasing temperature thereof.
Referring to FIG. 1, DC voltage and DC current fluctuate according to temperature change, but it can be seen that the DC current changes more than the DC voltage. In Korea, for example, since surface temperature of a solar cell and a solar cell module on which sunlight is incident rises up to a temperature of 55° at noon, relatively low current is generated in comparison to generated voltage of the solar cell or the solar cell module, and generating efficiency is significantly reduced.
In this case, natural cooling by wind and wind pressure difference is a way to increase the DC current without great cost, but existing solar cells and solar cell modules are provided with unventilated structures.
Meanwhile, in Korean Patent Application Publication No. 10-2016-0022662 (published on Mar. 2, 2016), although it has been disclosed that a ventilative space is provided between cover plates provided in upper part of a solar cell and a solar cell module, there is a limit to increase cooling efficiency because structures of the solar cell and the solar cell module cannot facilitate passage of wind through the solar cell.